This invention relates to a method of stuffing compressible products into flexible covers and apparatus therefor.
The insertion of a compressible product, such as a cushion or a soft filler for toys and dolls, into a flexible cover within which it is to be expanded so as to be conformed or shaped by the cover with a snug close fit has been a problem which has eluded satisfactory solution for many years. Thus the usual procedure of applying a cover to a cushion or to a soft compressible toy or doll body has been to rely upon the manual dexterity of the operator. However, regardless of the degree of dexterity which an operator can achieve, the operation is time consuming and costly. Also, in the case of large cushions, such as those used in recreational vehicles which commonly have dimensions in the order of a length of six feet, a width of at least twelve inches and a thickness of six inches, considerable strength must be exerted to manually apply the cover, even though the cover is of the type which has an opening at a side and/or end thereof which may be closed by slide fasteners when the cover has been applied in place around the cushion filler.
In cases where the cushion or other compressible filling is an open cell foam, such as polyurethane foam, a part of the problem or difficulty of applying a cover stems from the surface characteristics of the foam which tend to cling to or provide frictional resistance to application of the covers thereto. In other cushions using fillers such as feathers, down and kapok confined within an inner enclosure and to be inserted in an outer or finished enclosure, a similar problem of surface friction occurs during application of the outer cover.
Some efforts to deal with the problem have been made previously. An article in the monthly publication "Bedding" published by the National Association of Bedding Manufacturers in the issue of October, 1970, Volume 98, No. 10, pages 63-69 mentions tests of a method for encasing a filler, but does not disclose the structure or mechanism which was used in the test, and does not teach or suggest the apparatus herein disclosed.
Another example is an apparatus for mechanically squeezing the compressible filler by means of rollers to assist in applying a cover, but this has been found to have certain limitations which have prevented its general adoption and acceptance in industry.
Another example disclosed in U.S. Pat. No. 3,611,524, dated Oct. 12, 1971 involved wrapping a filler within a flexible gas impervious sheet having an opening to receive a vacuum head for evacuating air within the wrapper and the filler while a cover is applied around the sheet and filler, thus using the vacuum head to reduce the dimensions of the sheet-enclosed filler and also as a handle to assist in manipulating the reduced sheet-enclosed filler until the cover is fully applied upon the sheet-enclosed filler, whereupon the vacuum head is withdrawn from the sheet and filler.
Vacuum tables for holding work pieces of various types are shown in U.S. Pat. Nos. 1,851,028; 3,840,961; 3,884,061; 4,066,249 and Canadian Patent No. 678,465 dated Jan. 21, 1964, but none have been cantilevered to permit application of a cover over the table and the article supported thereon, and none teach the use of an air impervious sheet draped over the supported article and exposed apertures of the table to permit withdrawal of air from and collapse of an air pervious filler supported on the table. A hand held type of ring section assembly tool is shown in U.S. Pat. No. 3,224,106, but contains no suggestion that could assist in solving the problem of applying a cover to a collapsible filler.